1. Technical Field
The present invention relates to a solid-state imaging device and an imaging apparatus.
2. Related Art
JP-A-2007-103786 discloses a solid-state imaging device wherein the lights of “B” (blue) and “R” (red) are detected by a photodiode within a silicon substrate, while the light of “G” (green) is detected by a photoelectric converter over the silicon substrate.
In the solid-state imaging device, regarding the photoelectric converter over the silicon substrate, holes among charges generated in a photoelectric conversion layer are accumulated in a pixel electrode, and a signal corresponding to the accumulated holes is read out by a signal readout circuit which is formed of an n-channel MOS transistor. In the solid-state imaging device, regarding the photodiode within the silicon substrate, electrons among charges generated here are accumulated, and a signal corresponding to the electrons is read out by a signal readout circuit which is formed of an n-channel MOS transistor.
In accordance with the solid-state imaging device, regarding the photoelectric converter over the silicon substrate, the holes generated in the photoelectric conversion layer are used as the charges for the signal readout, whereby a sensitivity to the G light can be enhanced by making low a probability at which the charges generated in the photoelectric conversion layer are annihilated during the movements thereof within the photoelectric conversion layer, and a probability at which the charges are trapped by trap levels.
On the other hand, as to the B light and the R light, the charges need to be processed within the silicon substrate, and hence, the electrons which are higher in mobility than the holes are used as the charges for the signal readout. Thus, probabilities at which the electrons generated in correspondence with the B light and the R light are annihilated during the movements thereof can be made low, and also sensitivities to the R light and the B light can be prevented from lowering.
In general, the wide dynamic range is required for a solid-state imaging device and is also required in a solid-state imaging device stated in JP-A-2007-103786. However, the dynamic range enlargement is not stated in JP-A-2007-103786. Especially, a photoelectric-conversion-layer-stack-type solid-state imaging device which pulls out holes as charges for signal from the photoelectric converter over the silicon substrate, like the solid-state imaging device in JP-A-2007-103786, includes a readout circuit which is different from a readout circuit of a photoelectric converter using a general photo diode in a silicon substrate which pulls out electrons as charges for signal. For this reason, a devisal for the dynamic range enlargement is required.